U.S. Pat. No. 4,397,270 (=JP-A 55-137305) discloses a variable valve timing and lift system. It includes a driving shaft, a control rod with axially spaced eccentric cams, and a pivot structure. The pivot structure supports valve operating (VO) cams for pivotal motion above valve lifters of cylinder valves. Springs are mounted for the VO cams, respectively. Each of the springs biases one of the corresponding rocker cams toward its rest position where the associated cylinder valve closes. Rocker arms operate the VO cams, respectively. The eccentric cams, which are in rotary unison with the control rod, bear the rocker arms, respectively. An axis of each of the eccentric cams serves as the center of drive of the corresponding one of the rocker arms. Cams fixed to the driving shaft operate the rocker arms, respectively. An electronic control module (ECM) or a controller is provided. Sensors on the engine send information on engine speed, engine load, vehicle speed, and coolant temperature to the ECM. At a predetermined switchover point, the ECM sends a signal to an actuator for the control rod. As the actuator turns the control rod, the eccentricity of each of the eccentric cams with respect to an axis of the control rod changes. This alters the position of pivot axis of the rocker arms relative to the position of pivot axis of the VO cams. This causes variation in valve timing and lift of each of the cylinder valves.
It would be desired to keep the cylinder valves closed when so required during some engine operation mode. An object of the present invention is to provide a VVA apparatus that can keep the associated cylinder valve or valves closed. Specifically, the present invention aims at providing a VVA apparatus that can keep the associated cylinder valve or valves closed and that can be installed within a limited space above the engine cylinder head.